package lab02.test22;

/**
 * Created by dell on 2017/10/31.
 */
public class Test {
    public static String change(String b) {
        char letters[] = new char[b.length()];
        for(int i=0;i<b.length();i++){

            char letter = b.charAt(i);
            if(letter>='a' && letter<='z')
                letter = (char) (letter-32);
            else if(letter>='A' && letter<='Z')
                letter = (char) (letter+32);
            letters[i] = letter;
        }

        return new String(letters);
    }
    public static void main(String args[]) {

        System.out.println(change("SunSiYu"));

    }
}

